The lithified lower oceanic crust is one of Earth's last biological frontiers as it is difficult to access. It is challenging for microbiota that live in marine subsurface sediments or igneous ...basement to obtain sufficient carbon resources and energy to support growth
or to meet basal power requirements
during periods of resource scarcity. Here we show how limited and unpredictable sources of carbon and energy dictate survival strategies used by low-biomass microbial communities that live 10-750 m below the seafloor at Atlantis Bank, Indian Ocean, where Earth's lower crust is exposed at the seafloor. Assays of enzyme activities, lipid biomarkers, marker genes and microscopy indicate heterogeneously distributed and viable biomass with ultralow cell densities (fewer than 2,000 cells per cm
). Expression of genes involved in unexpected heterotrophic processes includes those with a role in the degradation of polyaromatic hydrocarbons, use of polyhydroxyalkanoates as carbon-storage molecules and recycling of amino acids to produce compounds that can participate in redox reactions and energy production. Our study provides insights into how microorganisms in the plutonic crust are able to survive within fractures or porous substrates by coupling sources of energy to organic and inorganic carbon resources that are probably delivered through the circulation of subseafloor fluids or seawater.
Many social insects display age polyethism: young workers stay inside the nest, and only older workers forage. This behavioural transition is accompanied by genetic and physiological changes, but the ...mechanistic origin of it remains unclear. To investigate if the mechanical demands on the musculoskeletal system effectively prevent young workers from foraging, we studied the biomechanical development of the bite apparatus in
leaf-cutter ants. Fully matured foragers generated peak
bite forces of around 100 mN, more than one order of magnitude in excess of those measured for freshly eclosed callows of the same size. This change in bite force was accompanied by a sixfold increase in the volume of the mandible closer muscle, and by a substantial increase of the flexural rigidity of the head capsule, driven by a significant increase in both average thickness and indentation modulus of the head capsule cuticle. Consequently, callows lack the muscle force capacity required for leaf-cutting, and their head capsule is so compliant that large muscle forces would be likely to cause damaging deformations. On the basis of these results, we speculate that continued biomechanical development post eclosion may be a key factor underlying age polyethism, wherever foraging is associated with substantial mechanical demands.
Abstract Background and Aims Hepatitis E is a zoonosis caused by hepatitis E virus (HEV), which was first discovered 40 years ago. It is the most prevalent hepatitis virus worldwide. Most hepatitis E ...cases are self-limiting acute hepatitis, but the virus has been recognized to cause chronic hepatitis. Following the first case report of chronic hepatitis E (CHE) in a transplant recipient, CHE has recently been identified as associated with chronic liver damage induced in immunocompromised patients such as transplant recipients. CHE can induce extra-hepatic manifestations, such as immune-mediated thrombocytopenia, neurological symptoms, and kidney injuries. Few cases of glomerulonephritis (GN) and cryoglobulinemia in transplant patients have been related with CHE, with a good progression thanks to viral control with ribavirin introduction. There have been no reported cases in the literature of good progress in renal function in renal transplant patients despite failure of treatment with Ribavirin. Method We report here what is to our knowledge, the first documented case of HEV-induced de novo cryoglobulinemic membranoproliferative glomerulonephritis in a renal transplant patient with a ten-year history of CHE infection unsuccessfully treated with ribavirin. Results A 69-year-old man underwent a kidney transplant for diabetes type 1. 7 years after transplantation, he was diagnosed with a chronic genotype 3.1H-HEV infection. He was treated by Ribavirin, but it did not allow to eradicate HEV but a biochemical response. At 18 years post transplant, he presented with asthenia, abdominal pains and increased liver enzyme levels: liver tests were disrupted with cytolysis and cholestasis. He presented also a nephritic syndrome with high blood pressure, oedemas, increased serum creatinine level, proteinuria with hypoalbuminemia and de novo microscopic hematuria. Biological analysis revealed presence of type 2 cryoglobulinemia with monoclonal IgM Kappa (2285 mg/L), and polyclonal immunoglobulins association. Rheumatoid factor was increased (573 UI/ml) and C4 level was reduced (0.04 g/L). The concentration of HEV RNA in the serum was 750 000 UI/mL. Viral serologies were performed for HBV, HCV, HAV, HIV, EBV, CMV. Hematologic diseases were ruled out by analyzing a bone marrow biopsy specimen. Histologic analysis of a kidney biopsy specimen revealed diffuse endocapillary proliferation, diffuse mesangial proliferation and focal glomerular basal membrane duplication. One arteriolar section showed a focal lesion of vasculitis (Fig. 1). There was no argument for allograft rejection. Immunofluorescence microscopy revealed mesangial and capillary wall deposits of IgM, IgG, C3 and C1q, polytypic for k and l light chains. We suspected cryoglobulinemic membranoproliferative glomerulonephritis induced by VHE. The initial treatment plan involved 10 sessions of plasmapheresis and steroid pulses (500 mg/d for 3 days), alongside a course of rituximab (1 g/week for 4 weeks). However, the patient experienced intolerance to rituximab, prompting a switch to Obinutuzumab. Subsequently, the anti-HEV therapy was modified, and the patient was placed on a course of Sofosbuvir. Consequently, three months after treatment kidney function kidney improved with return to baseline and cryoglobulinemia became undetectable. However, proteinuria remained impaired and VHE RNA was still present. Conclusion Cryoglobulinemia is rarely associated with glomerular disease in HEV infection, and cases currently reported in the literature showed a favorable outcome with ribavirin. This case is the first to display a chronic HEV infection with cryoglobulin-induced glomerulonephritis with global improvement despite unsuccessful treatment with ribavirin. Although the difficulty of managing immunity in the treatment of cryoglobulinemia by immunodepleting treatment, with the risk of increased viral replication in the absence of an effective antiviral, it seems interesting to offer a first-line treatment of cryoglobulinemia that appears to improve renal function despite continued viral replication. These results need to be confirmed in further studies.
Petunia and Calibrachoa are ornamental plants of worldwide economic importance. Commercially, it is useful to combine desirable characteristics of Calibrachoa, including the large diversity of flower ...colors, with the pH tolerance and vigorous growth of Petunia. For investigation of interspecific hybrids between Petunia and Calibrachoa we used four different introns with flanking exon areas, each from a different gene and with a different sequence for Petunia and Calibrachoa, as genus-specific markers for chromosomes in interspecific hybrids. PCR primers specific for Petunia and Calabrachoa were made from the determined sequences and tested on a range of presumed hybrids using multiplex PCR, which confirmed that the hybrids were derived from these two species. Flow cytometry demonstrated that the hybrids were triploid, and determination of chromosome numbers showed that two of the chromosome sets were from Calibrachoa, i.e. that the other parent, Petunia, was diploid. Similar methods can be used for molecular characterization of other new hybrids made between closely related species or cultivars.
Introduction
Epstein‐Barr virus (EBV) is a herpesvirus linked to pre‐malignant lymphoproliferative diseases and up to nine distinct human tumors. The most frequent EBV‐associated malignancies are ...lymphomas and nasopharyngeal carcinoma. By promoting smooth muscle proliferation, EBV can induce EBV‐associated smooth muscle tumors (SMT) which remain a very rare oncological entity. This study reports one case report of SMT and aims to offer the largest review of literature on post‐transplantation‐SMT (PT‐SMT) in kidney transplant recipients, with a focus on therapeutic management and evolution of graft function.
Methods
Case reports and case series of PT‐SMT in kidney transplant recipients were collected from 1996 to 2019.
Results
A total of 59 PT‐SMT were evaluated. The median time at diagnosis was 74.6 months after kidney transplantation. The most frequent localizations were liver and lung. EBV seroconversion was notified in all six patients with previously negative status. Preferred therapeutic option was surgery (65.9%), associated with a reduction in immunosuppression (77.2%), which includes switch to mTOR inhibitors (29.5%), and discontinuation of MMF (32%). In our review, 13% of patients experienced rejection, 8.7% lost their graft and went back on hemodialysis; 8.8% of patients died of PT‐SMT.
Conclusion
PT‐SMT is a rare but serious condition in kidney transplant recipients. EBV seroconversion following transplantation appears as a risk factor in developing PT‐SMT in solid‐organ recipients. In the absence of guidelines, therapeutic management for PT‐SMT is challenging and exposes the patient to high risk of graft loss.
Abstract
Objective
To identify characteristics of granulomatosis with polyangiitis (GPA) associated with induction failure, describe salvage therapies and their efficacy.
Methods
We conducted a ...nationwide retrospective case-control study of GPA with induction failure between 2006 and 2021. Each patient with induction failure was randomly paired to three controls matched for age, sex and induction treatment.
Results
We included 51 patients with GPA and induction failure (29 men and 22 women). At induction therapy, median age was 49 years. Twenty-seven patients received intravenous cyclophosphamide (ivCYC) and 24 rituximab (RTX) as induction therapy. Patients with ivCYC induction failure more frequently had PR3-ANCA (93% vs 70%, P = 0.02), relapsing disease (41% vs 7%, P < 0.001) and orbital mass (15% vs 0%, P < 0.01) compared with controls. Patients with disease progression despite RTX induction therapy more frequently had renal involvement (67% vs 25%, P = 0.02) with renal failure (serum creatinine >100 µmol/l in 42% vs 8%, P = 0.02) compared with controls. After salvage therapy, remission was achieved at 6 months in 35 (69%) patients. The most frequent salvage therapy was switching from ivCYC to RTX (or vice versa), showing an efficacy in 21/29 (72%). Remission was achieved in nine (50%) patients with inappropriate response to ivCYC, while in patients with progression after RTX induction, remission was achieved in four (100%) who received ivCYC (with or without immunomodulatory therapy), but only in three (50%) after adding immunomodulatory therapy alone.
Conclusion
In patients with induction failure, characteristics of GPA, salvage therapies and their efficacy vary according to induction therapy and failure modality.
Fibrinogen A α-chain amyloidosis (AFib amyloidosis) is a form of amyloidosis resulting from mutations in the fibrinogen A α-chain gene (FGA), causing progressive kidney disease leading to kidney ...failure. Treatment may include kidney transplantation (KT) or liver-kidney transplantation (LKT), but it is not clear what factors should guide this decision. The aim of this study was to characterize the natural history and long-term outcomes of this disease, with and without organ transplantation, among patients with AFib amyloidosis and various FGA variants.
Case series.
32 patients with AFib amyloidosis diagnosed by genetic testing in France between 1983 and 2014, with a median follow-up of 93 (range, 4-192) months, were included.
Median age at diagnosis was 51.5 (range, 12-77) years. Clinical presentation consisted of proteinuria (93%), hypertension (83%), and kidney failure (68%). Manifestations of kidney disease appeared on average at age 57 (range, 36-77) years in patients with the E526V variant, at age 45 (range, 12-59) years in those with the R554L variant (P<0.001), and at age 24.5 (range, 12-31) years in those with frameshift variants (P<0.001). KT was performed in 15 patients and LKT was performed in 4. In KT patients with the E526V variant, recurrence of AFib amyloidosis in the kidney graft was less common than with a non-E526V (R554L or frameshift) variant (22% vs 83%; P=0.03) and led to graft loss less frequently (33% vs 100%). Amyloid recurrence was not observed in patients after LKT.
Analyses were based on clinically available historical data. Small number of patients with non-E526V and frameshift variants.
Our study suggests phenotypic variability in the natural history of AFib amyloidosis, depending on the FGA mutation type. KT appears to be a viable option for patients with the most common E526V variant, whereas LKT may be a preferred option for patients with frameshift variants.
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